LED LIGHTING CONSIDERATIONS
Heather Johnson, LC, IES
April 23, 2015
Today’s Objectives:
How has the LED “revolution” changed the way we
figure lighting needs? What has changed, what is
the same?
 How
can you be sure you give your customers what
they need? What are the important facts to gather?
Where can we get easy, accurate, inexpensive
calculation software?
Lumen Maintenance – Traditional Sources
Source: U.S. Department of Energy | Energy Efficiency & Renewable Energy
Source: U.S. Department of Energy | Energy Efficiency & Renewable Energy
Also causing lower light levelsLamps Die!
The “average life” is
determined when 50% of
the lamps initially installed
are still operating.
90-100%
70-89%
50-69%
Failed
Time 12,000 hours
Economic vs. Rated Life of Traditional Systems
Source: Venture Lighting
Lumen Maintenance Comparison
HPS
PSMH
CMH
INDUCTION
LED (L70)
Rated Life (HRS)
24,000
15,000-20,000
15,000-20,000
100,000
50,000-120,000
Lumen Maintenance
70-80%
40-59%
70%
60%
90-95%
Mortality Rate
35%
55%
50%
40%
?
Lumen Maintenance Comparison
Light Loss Factors
If leds last “forever” why can’t we use
1.0 for LLF
What are the factors that cause light
levels to drop
How different are these factors from
what we’re used to
Lumen Maintenance: HID vs. LED
The “Old” Story
Lumen Maintenance: HID vs. LED
The “New” Story
Understanding Lumen Maintenance
Current Methodology of reporting Lumen
Maintenance:
1. Reference singular Lxx values tied to undisclosed operating ambient
temperature
2. Intentionally relate the Lxx value to the legacy source (ex: L90 to
Fluorescent)
3. Provide reference table for customer to identify implications of
anticipated operating ambient temperature
So the big difference In using LEDs
1.
2.
3.
4.
5.
Lumen Maintenance – the light level stays even
System Life – much longer, we do not even know yet
Energy cost saving$
Better uniformity of Light
Ease of controls
 Instant-on
 On-off switching
 Dimming
How Long do they Last?
50,000 Hours
•
•
•
•
•
•
•
130 Years at 1 hour/day
68.5 Years at 2 hours/day
34.2 Years at 4 hours/day
22.8 Years at 6 hours/day
17.1 Years at 8 hours/day
11.4 Years at 12 hours/day
5.7 Years at 24 hours/day
Verify
• Ask for proof of lumen maintenance,
ask for the LM80 data. This
information should be readily
available
• LEDs can last a very long time, but
remember that this is predicated on
good thermal performance
Choosing an LED lighting systemA long term decision
Light Loss Factor – Dirt Depreciation
The one factor that has NOT changed in favor of
LEDs.
In fact, you may need to take out MORE to
account for dirt because they will last longer, not be relamped
they will not be cleaned BECAUSE they aren’t
relamped
Luminaire Dirt Depreciation Affects All
Systems
Category of Luminaire
Operating Environment
• Clean: filtered air circulation; retail, offices, institutional
• Moderate: air enters through windows, doors, non-filtered; light industry or
manufacturing
• Dirty: normal activities produce significant dirt
Industrial Luminaires
Industrial Luminaires have 6 maintenance
categories, and 15 environments to consider.
Dirt Depreciation Over Time
Luminaire Dirt Depreciation –
LDD (Outdoor)
Luminaire Cleaning
• Collect recommended cleaning
procedures from luminaire
manufacturers
• Evaluate location types
• Determine optimum cleaning
frequency.
• Do periodic audits
• Contrary to expectations, LED
luminaires will acquire dirt and need
to be cleaned
LDD Field Testing Results from DOE Projects
LDD ~ 3-5% per year over 1-2 year period. More studies needed. Only 2 sites,
very limited data & length of service.
LDD/Yr
3.7%
3.0%
5.3%
4.2%
To Summarize Light Loss Factors
HID, Fluorescent:
• LLD x BF x LDD = Total Light Loss Factor
• LLD should include mortality
• Sometimes Ambient Temperature Factor, Lamp Tilt
Factor
LED (SSL):
• LMF x LDD = Total Light Loss Factor
• Sometimes Ambient Temperature Factor
Sources of Site Information
Where does the project site information come
from?
Best case
What is in-between?
Worst case
Necessary Data
The data needed to complete most jobs is as follows:
•
•
•
•
•
•
•
•
•
•
Fixture type, spec sheet, & IES file
Fixture locations, if existing
Mounting height & type
Surface reflectances: ceiling, walls, floor (indoors)
Footcandle criteria
Maintenance plans
Light loss factor (LLF)
Interior: Ceiling height
Exterior: Building height
Correctly scaled site or building plan
Cad File = Best case
PDF Files
• Easily transmitted
electronically
• Easily opened by most
everyone
• Can be printed to any
size
• Can magnify and print
certain areas
• Can be marked using
editing tools found
within the software
• Not easily cleaned of
extraneous material
• No dimension lines, hard to
confirm scale
• PDF converting software
available
• Large file size
• Colors and hatching do
not convert
• Text becomes distorted,
sometimes illegible
Data Source Type 3
PDF Files- scale??
• Insert example
Satellite imagery as survey
• Gaining popularity
• Saves cost of actual
site survey
• Image files easily
shared electronically
• Easier for older sites
when no drawings
exist
• Many sites provide
visibility
• Google, Zillow,
Bing
• Heavy landscaping limits
visibility
• Skewed views are common
• Dimensions are estimates or
not available
• Requires time-consuming
AutoCAD trace
• Accurate scaling is not
possible
• “Zooming in” can result in
pixilation and fuzziness.
Data Source Type 4
Satellite Imagery
Example
This site looks pretty clear right?
Let’s zoom in to find pole locations.
Can you outline
the shape of that
island?
Can you tell where
that pole is?
Can you accurately
dimension with those
parking spaces?
Satellite Imagery Considerations
• Tracing can add 2-8 hours of additional
work
• Landscaping may hinder visibility of
pertinent details
• If image is old, additions or site
modification may not be shown
• Incorrect scaling can result in lighting
errors
• Skewed view will distort shapes
Satellite Imagery Considerations
Cocktail napkin, verbal description
Data Source Type 5
Sources for lighting software
• Lighting Manufacturers
– Design tools available online
– Software program available for a fee
– Sophisticated program available for free
• Independent software companies
– Fairly steep fee to pay for all upkeep, profit
– Must pay for training and annual renewal